U.S. Global Change Research Program: USGCRP conducts state-of-the-art research to understand the interactive processes that influence the total Earth system—which includes the atmosphere, oceans, land, ice, ecosystems, and people.

This comprehensive resource draws on the connections between the environment and a variety of disciplines such as agriculture, education, law, health and technology. Topics covered include global climate change, green building, pollution, sustainable agriculture, renewable energy, recycling and more. Indexing and abstracts for more than 612,000 records.

This search engine can help you "home in on key publications, citation, and results..." on your topic. Once you hone in an article, there are automatic recommendations to other related citations, sorted by influence. It is mostly focused on computer science and neuroscience topics.

An open access repository for research data, including journal articles, datasets, and software. Currently contains mostly scientific research data, but open to all subjects. Affiliated with CERN and OpenAIRE.